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POST-DIVIDER SETTINGS

RECOMMENDATIONS FOR OSCILLATOR GAIN

CDCE401

SCAS820 – JUNE 2006

PD2

PD1

PD0

POST-DIVIDER SETTINGS

COMMENT

0

0

0

Post-divider

× 1

Default

0

0

1

Post-divider

× 1/2

0

1

0

Post-divider

× 1/4

0

1

1

Post-divider

× 1/8

1

0

0

Post-divider

× 1/16

1

0

1

Post-divider

× 1/32

1

1

0

Post-divider

× 1 (like in default).

1

1

1

No division: The post-divider setting PD[2:0] = 111 is used to turn off the amplifier after the

oscillator core. This offers the capability to disable effectively all blocks except the oscillator

(1)

Setting core current consumption too high impacts the crystal drive power, which affects crystal performance and lifetime.

OG[1:0]

OP[2:0]

OSCILLATOR OSCILLATOR OPERATING FREQUENCY

COMMENT

11

000

Oscillator gain for 20 MHz

≤ frequency < 40 MHz

Default

10

000

Oscillator gain for 40 MHz

≤ frequency < 60 MHz

01

000

Oscillator gain for 60 MHz

≤ frequency < 80 MHz

00

000

Oscillator gain for 80 MHz

≤ frequency ≤ 100 MHz

(2)

whole supply voltage range. Depending on the crystal series equivalent resistance, the OP[2:0] bits might require different settings.

Contact TI for assistance.

10

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